Yes al things help
I had already firurd out a 4th, that is flatten image in photoshop

is your Visual Panel > Effect > Effect List 
include "Static Noise"?

if Yes

1. uncheck Static Noise

or

2. in Photoshop 
add background in first (bottom) layer (black or white or same image that you rendered)
total will be two layers

or

3. in IC render image format set to jpg (don't use png or tga)


hope this will help